1. Field of the Invention
The present invention generally relates to an air cleaner unit for a combustion engine mounted on a working vehicle such as a lawn tractor and, more particularly, to the structure of the air cleaner unit that is excellent in maintenance including, for example, replacement of a filter element and/or interior cleaning of a cleaner case.
2. Description of the Prior Art
Some of the general-purpose combustion engines currently mounted on working vehicles include an air cleaner unit mounted atop a carburetor. For example, U.S. Pat. No. 4,537,160, issued Aug. 27, 1985, to Shirai and assigned to Kawasaki Jukogyo Kabushiki Kaisha, discloses an air cleaner unit including a cleaner case of two-piece construction including upper and lower case components, which are in the form of a top cover and a case body, respectively. The cleaner case is fluidly connected with an inlet tube by bolts or nuts.
Since the cleaner case employed in the prior art air cleaner unit is of two-piece construction including the case body and the top cover mounted on the case body to close the top opening of the case body, replacement of a filter element accommodated within the case body requires removal of the top cover, followed by removal of the used filter element from the case body in readiness of loading of a fresh filter element. Because of this replacement procedure, during the replacement of the filter element, dust and dirt sticking to the used filter element tend to separate from the used filter element and then fall into the case body, eventually entering the combustion engine. While during the maintenance of the air cleaner unit cleaning of the cleaner case is also required, the cleaner case of the two-piece construction requires the top cover and the case body to be individually removed, resulting in a complicated and time-consuming work.